When I was looking for a book for the Microcontroller I pronounced it as "Ar dwee noh" and the sales person knew exactly what I was talking about. Two weeks prior to me asking, I guess another customer was asking for the same thing, so in the Northwest US, we pronounce it "ar dwee noh".

I am a new member in this forum. Meaning of "Arduino" is an open-source electronics prototyping platform, designed to make the process of using electronics in multidisciplinary projects more accessible.